This device can be used as an external stereo mic when mounted on top of a DSLR or camcorder since the headphone port is also a line out port. When using it as an external mic, you need to have the recorder either in standby mode (i.e. press the rec button once, then the record light flashes) or in rec mode (i.e. press the rec button twice, then the record light is on, the audio is going to be recorded in the Zoom audio recorder as well.)